one function used to change variable in another function - python-3.x

Question

# making a basic calendar
#list of months and their days
month_day = [[1,'January',31],[2,'February',28],
[3,'March',31],[4,'April',30],
[5,'May',31],[6,'June',30],
[7,'July',31],[8,'August',31],
[9,'September',30],[10,'October',31],
[11,'November',30],[12,'December',31]]
#checksum for new year
def isleapyear(year):
if year%4 == 0:
if year%100 == 0:
if year%400 == 0:
month_day[1][2] = 29
else:
month_day[1][2] = 28
else :
month_day[1][2] = 29
else:
month_day[1][2] = 28
#editable date (supposed to be
def Date():
year = 1
day = 31
month = 1
isleapyear(year)
date = [day, month_day[month-1][1], year]
return date
#function to increase day counter by 1
def new_day():
#checksum for month or year rollover
if Date.day == month_day[Date.month-1][2]:
Date.day = 1
if Date.month == 12:
Date.month = 1
Date.year = Date.year + 1
else:
Date.month = month + 1
else:
Date.day = Date.day + 1
new_day()
print (Date())
I am trying to teach myself python, so I have made a project a few smaller projects working together and one of them is a Date tracker. The Date function works. however when i try to call the new day function to bump the day by 1 and change month and year if needed, i get an error "AttributeError: 'function' object has no attribute 'day'". I understand that inside a function is a separate local variable not a global and that your not supposed to make global variables constantly changing. So I'm trying to get one function to call and use anothers variable I plan on making it into a button that changes the day by 1 or 7, I'm just having trouble visualizing how to get the function working. Any direction or help with getting this to work would be greatly appreciated
Thank you all in advance!

Answer 1

Firstly, you can't get variables from function.
One way you can deal with it is in function Date add line global year, day, month, this will make variables year, day, month global so you can use it in all function and outside of functions. And in new_day remove Date..
This should get rid of your problem.
Date.day would only work if Date was class not function.
For example:
class Date:
def __init__(self):
self.year = 1
self.day = 31
self.month = 1
Date().year # Should return 1
Date().day # Should return 31
Date().month # Should return 1